In recent years, the flip-chip bonding has been used as a method of mounting a semiconductor chip applicable to further higher density and higher frequency of wiring and the like of the semiconductor device. The flip-chip bonding is a technique of electrically connecting the semiconductor chip and a substrate using bumps (solder balls or the like). Generally, in the flip-chip bonding, a gap between the semiconductor chip and the substrate is sealed with a material called an underfill in order to reinforce around the bump.
Conventionally, in the flip-chip bonding, a method of manufacturing the semiconductor device (hereinafter, referred to as a post-supply type process) has been performed in which the bump of the semiconductor chip and the wiring of the substrate are joined by soldering or the like, and then an underfill agent which is a thermosetting liquid sealing resin composition is injected into a gap between the semiconductor chip and the substrate. In order to make products smaller and more reliable, it is required to narrow the gap. Therefore, in order to narrow the gap, flip-chip mounting using copper pillar for the bump of the semiconductor and a wiring terminal of the substrate has been developed. However, in the post-supply type process, there has been a problem in narrowing the gap.
In recent years, the pre-supply type process has attracted attention. In this process, first, the underfill agent is applied to the substrate and the semiconductor chip is placed thereon. Thereafter, curing of the underfill agent and connection between the bump of the semiconductor chip and the wiring terminal of the substrate are simultaneously performed. Thus, it is possible to shorten the process and shorten a curing time. As a result, it is possible to manufacture the semiconductor device at low cost and low energy. The liquid sealing resin composition (hereinafter, referred to as a pre-supply type liquid sealing resin composition) for the pre-supply type process has been studied.
The present inventors studied improvement of the resin composition (Patent Literature 1) containing (A) a specific EO-modified bisphenol A dimethacrylate, (B) a specific tricyclodecanedimethanol diacrylate, (C) an acid copolymer of butadiene and maleic anhydride, (D) an organic peroxide, and (E) a silica filler, as the resin composition which can be used in the pre-supply type process and has a thermal expansion coefficient relatively lower than that of an epoxy resin. A purpose of this study is to impart further durability to the resin composition while maintaining conventional mounting characteristics.
In the improvement of the above-mentioned resin composition, it has been found that an ultraviolet-curable composition for optical disk characterized by containing a predetermined branched epoxy (meth) acrylate (E1) and that the branched epoxy (meth) acrylate (E1) has a weight average molecular weight of 1,000 to 10,000 by gel permeation chromatography is disclosed (Patent Document 2). The ultraviolet-curable composition is used for a light transmitting layer of the optical disk laminated with at least a light reflecting layer and the light transmitting layer on the substrate and reproducing information by irradiating a laser beam from the light transmitting layer side.